<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<title>Source code</title>
<link rel="stylesheet" type="text/css" href="../../../../../stylesheet.css" title="Style">
</head>
<body>
<div class="sourceContainer">
<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: PrefixKVDatabase.html 878 2015-04-17 01:32:03Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.kv.util;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import org.jsimpledb.kv.KVDatabase;<a name="line.10"></a>
<span class="sourceLineNo">011</span><a name="line.11"></a>
<span class="sourceLineNo">012</span>/**<a name="line.12"></a>
<span class="sourceLineNo">013</span> * Prefix {@link KVDatabase} implementation.<a name="line.13"></a>
<span class="sourceLineNo">014</span> *<a name="line.14"></a>
<span class="sourceLineNo">015</span> * &lt;p&gt;<a name="line.15"></a>
<span class="sourceLineNo">016</span> * Instances use a fixed {@code byte[]} key prefix for all key access, thereby providing a nested {@link KVDatabase}<a name="line.16"></a>
<span class="sourceLineNo">017</span> * view of the corresponding sub-range of keys within the containing {@link KVDatabase}. This allows, for example, multiple<a name="line.17"></a>
<span class="sourceLineNo">018</span> * {@link KVDatabase}s to exist within a single containing {@link KVDatabase} under different key prefixes.<a name="line.18"></a>
<span class="sourceLineNo">019</span> * &lt;/p&gt;<a name="line.19"></a>
<span class="sourceLineNo">020</span> */<a name="line.20"></a>
<span class="sourceLineNo">021</span>public class PrefixKVDatabase implements KVDatabase {<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>    private final KVDatabase db;<a name="line.23"></a>
<span class="sourceLineNo">024</span>    private final byte[] keyPrefix;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>    /**<a name="line.26"></a>
<span class="sourceLineNo">027</span>     * Constructor.<a name="line.27"></a>
<span class="sourceLineNo">028</span>     *<a name="line.28"></a>
<span class="sourceLineNo">029</span>     * @param db the containing {@link KVDatabase}<a name="line.29"></a>
<span class="sourceLineNo">030</span>     * @param keyPrefix prefix for all keys<a name="line.30"></a>
<span class="sourceLineNo">031</span>     * @throws IllegalArgumentException if {@code db} or {@code keyPrefix} is null<a name="line.31"></a>
<span class="sourceLineNo">032</span>     */<a name="line.32"></a>
<span class="sourceLineNo">033</span>    public PrefixKVDatabase(KVDatabase db, byte[] keyPrefix) {<a name="line.33"></a>
<span class="sourceLineNo">034</span>        if (db == null)<a name="line.34"></a>
<span class="sourceLineNo">035</span>            throw new IllegalStateException("null db");<a name="line.35"></a>
<span class="sourceLineNo">036</span>        if (keyPrefix == null)<a name="line.36"></a>
<span class="sourceLineNo">037</span>            throw new IllegalStateException("null keyPrefix");<a name="line.37"></a>
<span class="sourceLineNo">038</span>        this.db = db;<a name="line.38"></a>
<span class="sourceLineNo">039</span>        this.keyPrefix = keyPrefix.clone();<a name="line.39"></a>
<span class="sourceLineNo">040</span>    }<a name="line.40"></a>
<span class="sourceLineNo">041</span><a name="line.41"></a>
<span class="sourceLineNo">042</span>    /**<a name="line.42"></a>
<span class="sourceLineNo">043</span>     * Get the containing {@link KVDatabase} associated with this instance.<a name="line.43"></a>
<span class="sourceLineNo">044</span>     *<a name="line.44"></a>
<span class="sourceLineNo">045</span>     * @return the containing {@link KVDatabase}<a name="line.45"></a>
<span class="sourceLineNo">046</span>     */<a name="line.46"></a>
<span class="sourceLineNo">047</span>    public KVDatabase getContainingKVDatabase() {<a name="line.47"></a>
<span class="sourceLineNo">048</span>        return this.db;<a name="line.48"></a>
<span class="sourceLineNo">049</span>    }<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span>    /**<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * Get the key prefix associated with this instance.<a name="line.52"></a>
<span class="sourceLineNo">053</span>     *<a name="line.53"></a>
<span class="sourceLineNo">054</span>     * @return (a copy of) this instance's key prefix<a name="line.54"></a>
<span class="sourceLineNo">055</span>     */<a name="line.55"></a>
<span class="sourceLineNo">056</span>    public final byte[] getKeyPrefix() {<a name="line.56"></a>
<span class="sourceLineNo">057</span>        return this.keyPrefix.clone();<a name="line.57"></a>
<span class="sourceLineNo">058</span>    }<a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span>    @Override<a name="line.60"></a>
<span class="sourceLineNo">061</span>    public PrefixKVTransaction createTransaction() {<a name="line.61"></a>
<span class="sourceLineNo">062</span>        return new PrefixKVTransaction(this);<a name="line.62"></a>
<span class="sourceLineNo">063</span>    }<a name="line.63"></a>
<span class="sourceLineNo">064</span>}<a name="line.64"></a>
<span class="sourceLineNo">065</span><a name="line.65"></a>




























































</pre>
</div>
</body>
</html>
